This invention relates generally to hand tools. More specifically, the present invention relates to a shovel utilizing a composite socket to attach a tool handle to the blade, and a process for manufacturing such shovels.
With the advent of the technology of forging steel billets into hand tools, the highest quality shovel blade was made by heating a billet of steel and hammering it into a form that provided a blade appropriately styled to scoop or dig earth. Because the blade was forged, the attack edge could be made appropriately thin, and as the blade progressed back towards the handle, it could be made thicker to give the blade the amount of stiffness and strength required in the use of the shovel. Originally, emanating from the center of the back or rear edge of the shovel blade, was a tang (as opposed to a socket) similar to the tangs commonly used today in rakes and hoes. The tang was subsequently jammed into a hole in a wooden handle, and an appropriate steel sleeve was provided over the end of the handle to provide the breakout resistance strength required.
The forged shovel, to this day, is the absolute top of the line for a number of reasons. Such shovels have blades which provide a relatively thin, sharp attack edge, that thicken out as the blade approaches a rear edge to provide stiffness and strength, and which provide a substantially flat surface on the underside of the blade to preclude the collecting of mud and clay. Further, forged shovels usually accommodate a good-sized tread on which the workman's foot can comfortably step, and may be reinforced by having extra steel in those areas of the blade surrounding the handle-engaging tang.
Over the years evolution and competition have brought about the manufacture of shovel blades from flat, cold-rolled sheet steel, which could be produced at a fraction of the labor costs of the forged blades. However, many concessions were made in the design of such newer stamped blades, which the marketplace has accepted because of the substantially lower costs of these blades notwithstanding their inferior characteristics.
For example, in modern stamped shovel blades, the back end of the dish is formed into a standing rib to provide a minimum acceptable level of stiffness. In contrast, the forged blade typically included more massive steel located in that location. By creating a standing rib in modern shovel blades to provide stiffness, a corresponding hollow is created on the underside of the blade which traps mud and clay. In more demanding applications, a flat plate is welded over the backside of the shovel indentation to simulate the "closed" back of the forged shovel. This is a problem addressed in U.S. Pat. Nos. 5,213,014 and 5,310,230 the contents of which are incorporated herein.
Further, to economize on the manufacturing operation, the original blank of the stamped blade includes a projection which when rolled into a circle provides a socket for the shovel handle. At the transition from the socket created for acceptance of the handle and the tread on which the workman's foot must rest, there is but the one thickness of the original steel sheet. This area of stamped blades is known to be a weak point which fails and rips when the shovel is heavily loaded. Moreover, since the socket circle or ring is not ordinarily locked in a closed position by welding, a hole is drilled in it to accept a rivet which provides the attachment for the handle in the socket and to keep the ring or circle closed. Furthermore, because the blade and socket are all made from one stamped piece of sheet steel, the area between the end of the shovel handle and the handle socket as it meets the blade should be filled with something (usually a piece of wood) to keep it from collapsing, which may occur when the shovel is used as a pry. This particular problem is addressed in U.S. Pat. No. Re. 32,364, the contents of which are incorporated herein.
From the foregoing it is readily seen that when industry attempted to reduce the cost of a shovel going from the forged model to the stamped model, a great number of concessions were made which the public has learned to accept. In addition to those noted above, a further concession in the stamped shovel has been the continuing extension of the socket length to accommodate a decline in the grade of wood available for handles. This, of course, compounds the concessions by using more steel and having a greater amount of scrap--that portion of the blank that is thrown away outboard on either side of the socket in its flat pattern.
Accordingly, there has been a need for an improved shovel design which utilizes the advantages inherent in stamped shovel blades, but eliminates the concessions in strength and durability in comparison with forged blades. Such a shovel would preferably permit the shovel blade to be produced using roughly half the area of the sheet metal stock typically required in the manufacture of conventional stamped shovel blades. Further, the improved shovel should provide a shovel blade having an improved and increased step or tread for the workman's foot, which may also serve as a stiffening member for the shovel blade itself, and provide for attachment of the handle at a point on the blade which will aid in the stiffness thereof and in dispersion of the load thereon. Moreover, such a shovel should have a substantially flat back surface for the shovel blade, to eliminate any mud and clay trap or the need to add a frog or cover. Additionally, such an improved shovel should accommodate modern composite resin tool handles. The present invention fulfills these needs and provides other related advantages.